import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';

function calculateWinner(squares) {
    const lines = [
        [0, 1, 2],
        [3, 4, 5],
        [6, 7, 8],
        [0, 3, 6],
        [1, 4, 7],
        [2, 5, 8],
        [0, 4, 8],
        [2, 4, 6],
    ];
    for (let i = 0; i < lines.length; i++) {
        const [a, b, c] = lines[i];
        if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
            return {
                winner: squares[a],
                line: lines[i]
            };
        }
    }
    return null;
}

function Square(props) {
    return (
        <button className={`square ${ props.result ? 'result' : ''}`} onClick={props.onClick}>
            {props.value}
        </button>
    );
}

function Board(props) {
    function renderSquare(i) {
        let result = false;
        if (props.line.indexOf(i) > -1)
            result = true;
        return (
            <Square
                value={props.squares[i]}
                onClick={() => props.onClick(i)}
                result={result}
            />
        )
    }
    function renderAllSquares() {
        let arrCol = [];
        let counter = 0;
        for (let i = 0; i < 3; i++) {
            let arrRow = [];
            for (let j = 0; j < 3; j++) {
                arrRow.push(renderSquare(counter++));
            }
            arrCol.push(
                <div className="board-row">
                    {arrRow}
                </div>
            )
        }
        return arrCol;
    }
    return renderAllSquares();
}

class Game extends React.Component {
    constructor() {
        super();
        this.state = {
            history: [{
                squares: Array(9).fill(null)
            }],
            stepNumber: 0,
            xIsNext: true,
            order: 'asc',
            selected: -1,
            line: []
        };
    }
    handleClick(i) {
        const history = this.state.history.slice(0, this.state.stepNumber + 1);
        const current = history[history.length - 1];
        const squares = current.squares.slice();
        if (squares[i] || calculateWinner(squares))
            return;

        squares[i] = this.state.xIsNext ? 'X' : 'O';
        this.setState({
            history: history.concat([{
                squares: squares
            }]),
            stepNumber: history.length,
            xIsNext: !this.state.xIsNext,
        });
    }
    jumpTo(step) {
        this.setState({
            stepNumber: step,
            xIsNext: !(step % 2),
            selected: step
        })
    }
    render() {
        const history = this.state.history;
        const current = history[this.state.stepNumber];
        const winner = calculateWinner(current.squares) ? calculateWinner(current.squares).winner : null;
        if (winner && this.state.line.length === 0) {
            this.setState({
                line: calculateWinner(current.squares).line
            });
        }

        const moves = history.map((step, move) => {

            const desc = move ? 'Move #' + move : 'Game start';
            return (
                <li key={move}>
                    <a href="#" className={this.state.selected === move ? 'result' : ''} onClick={() => this.jumpTo(move)}>{desc}</a>
                </li>
            );
        });

        if (this.state.order === 'desc')
            moves.reverse();

        let status;
        if (winner) {
            status = 'Winner: ' + winner;
        } else {
            status = 'Next player: ' + (this.state.xIsNext ? 'X' : 'O');
        }

        return (
            <div className="game">
                <div className="game-board">
                    <Board
                        line={this.state.line}
                        squares={current.squares}
                        onClick={(i) => this.handleClick(i)}
                    />
                </div>
                <div className="game-info">
                    <div>{status}</div>
                    <ol>{moves}</ol>
                </div>
                <button onClick={() => this.setState({order: this.state.order === 'asc'? 'desc' : 'asc'})}>切换升序/降序</button>
            </div>
        )
    }
}

ReactDOM.render(
    <Game/>,
    document.getElementById('root')
);